The invention concerns an electric compressed-gas power circuit breaker with a switching gap formed by two base contacts and a movable bridging contact which in the breaker opening operation slides off of the one base contact, the run-off contact, and moves in the direction toward the other base contact. Such a compressed-gas power circuit breaker is known, for instance, in U.S. Pat. No. 3,789,175 in the form of a blast-piston circuit breaker.
It is an object of the invention to reduce the switching energy in a compressed-gas power circuit breaker of the abovementioned type.
To solve this problem, it is known to control the motion of the bridging contact member by an electrodynamic coil system through whose primary coil the current to be interrupted flows. In this connection, reference may be had to Deutsche Offenlegungsschrift No. 2,304,904.
In co-pending U.S. patent application Ser. No. 539,951, filed Jan. 10, 1975, a contact arrangement for an electric pressure-gas circuit breaker is disclosed wherein a follower contact is associated with the run-off contact. The follower contact is insulated with respect to the run-off contact and is movable in the direction toward the other base contact which is stationary against the force of a spring. Also, the follower contact is connected with the current supply to the runoff contact through two coaxial coils, of which the one is stationary and the other is mechanically connected with the follower contact in such a manner that the bridging contact member runs up onto the follower contact when it separates from the run-off contact and the current to be interrupted is commutated onto the circuit branch containing the coils whereby a force acting on the follower contact in the direction toward the other stationary contact is produced between the coils.